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2015

Acute ankle and knee injuries: To x-ray or not?

G Fulde The University of Notre Dame Australia, [email protected]

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This article was originally published as: Fulde, G. (2015). Acute ankle and knee injuries: To x-ray or not?. Medicine Today, 16 (11), 48-52.

Original article available here: https://medicinetoday.com.au/mt/november-2015

This article is posted on ResearchOnline@ND at https://researchonline.nd.edu.au/med_article/836. For more information, please contact [email protected]. This article originally published: - Fulde, G., (2015) Acute ankle and knee injuries: To x-ray or not? Medicine Today, 16(11): 48- 52. Permission granted by Medicine Today for use on ResearchOnline@ND. © Medicine Today 2015 (http://www.medicinetoday.com.au). EMERGENCY MEDICINE PEER REVIEWED Acute ankle and knee injuries To x-ray or not?

GORDIAN FULDE MB BS, FRACS, FRCS(Ed), FRCS/FRCP(A&E)Ed, FACEM The Ottawa ankle and knee rules are validated clinical decision tools that guide clinicians in targeting radiology to those patients who are likely to have an ankle or knee fracture, thus minimising x-ray exposure of patients and reducing costs.

cute injuries to the ankle and knee target x-rays to those patients who are likely This article discusses the Ottawa rules joints are common and patients to have a fracture and not those that almost used to guide clinicians in the investiga- Ausually present to an emergency certainly do not. Such clinical tools or rules tion of acute ankle and knee injuries. department or a general practice. Differ- must have a very high sensitivity and entiating soft tissue injuries from fractures ­reasonable specificity to be helpful. What are the Ottawa Rules and is important because the management of Acute knee injuries account for over do they work? these two groups differ. Medical practi- one million emergency room visits in the In 1992, a set of criteria was developed tioners are becoming increasingly aware USA annually.1 Ankle injuries are even that used clinical signs to determine if an of the accumulative effects of x-rays and more common, and have been shown to x-ray should be performed for an acute there is a move to minimise x-ray exposure, be one of the most common presentations ankle injury – the Ottawa ankle rules especially in younger patients. Clinical to an emergency department.2 These inju- (Box 1 and Figure 1).6 The criteria have tools have been developed to help clinicians ries are rarely life- or limb-threatening been shown to have a sensitivity of 100% but cause significant pain and disability and a specificity of 40.1% for detecting for the patient. It has been shown that malleolus fractures and result in a 36% most patients presenting with knee and reduction in radiography.6 The rules have ankle injuries in the early 1990s under- also been shown to reduce the time went radiographic examination, and that patients spend in emergency departments, more than 92% of this imaging for knees without reducing patient satisfaction.7 and 85% for ankles did not show a Pain in the midfoot region is covered by fracture.­ 2,3 The incidence of fracture in the Ottawa foot rules, which are often acute knee injury is less than 5%.4 The grouped with the ankle rules, as shown individual cost of a radiograph is not high in Box 1. MedicineToday 2015; 16(11): 48-51 but the high frequency at which they are The Ottawa knee rules developed

Professor Gordian Fulde is Director of Emergency requested results in significant cost and later, in 1995, showed similar success to Medicine at St Vincent’s Hospital, Sydney; unnecessary irradiation for patients. the ankle rules, with a sensitivity of 98.5 Professor in Emergency Medicine at The University ­Furthermore, it has been suggested that to 100% and a specificity of 49% for of Notre Dame, Sydney; and Associate Professor radiography adds little information to a detecting fractures (Box 2 and Figure in Emergency Medicine at the University of New well performed­ clinical history and 2).8,9 Furthermore, the Ottawa knee rules

South Wales, Sydney, NSW. 5 RESEARCHERS/GETTY PHOTO IMAGES examination. were shown to be superior when ©

48 MedicineToday ❙ NOVEMBER 2015, VOLUME 16, NUMBER 11 Permission granted by Medicine Today for use on ResearchOnline@ND. © Medicine Today 2015 (www.medicinetoday.com.au) compared with other tools for assessing 6 knee injuries, i.e. the Pittsburgh knee 1. THE OTTAWA ANKLE RULES rules, the Weber and colleagues rule and the Fagan and Davies rule.10 Use of the In patients with acute ankle injury, an ankle x-ray is necessary if there is: Ottawa knee rules has been shown to • Pain over the malleoli of the ankle and one or more of – lead to a relative reduction in radio­ – patient is aged 55 years or older –– inability to bear weight both immediately and in emergency department 11 graphy of 37%. –– bone tenderness at the posterior tip of either the lateral or medial malleolus or The Ottawa ankle rules are not used the posterior 6 cm superior to either malleolus (Figure 1) in patients who are younger than 18 years, In patients with acute ankle injury, a foot x-ray is necessary if there is: pregnant or intoxicated, or if they have • Pain in the midfoot and either of distracting painful injuries, diminished –– bone tenderness at the navicular or the base of the fifth metatarsal (Figure 1) ­s­ensation in the legs or gross swelling –– inability to bear weight both immediately and in the emergency departmen ­preventing palpation of malleolar tenderness. Lateral view Uptake and utilisation of these rules has been variable.11-13 Posterior edge or tip of lateral malleolus Case scenarios 6 cm Medial view Case 1. A possible ankle fracture Posterior edge or tip of medial A 45-year-old woman limped into the malleolus emergency department one afternoon with the assistance of her husband and Navicular clearly in a lot of pain. She explained to 6 cm the triage nurse that she was carrying out her usual daily activities when she tripped over her dog at home, rolling her Base of fifth metatarsal ankle. The woman was unable to bear weight on her left leg. On closer physical examination, the left lower limb was Figure 1. Ottawa ankle rules – regions of bone tenderness. (Purple indicates malleolar neurologically intact with normal zone; green indicates midfoot zone.) pulses, there was gross swelling around Adapted from Stiell et al., Ann Emerg Med 1992; 21: 384-390.6 the lateral malleolus, marked tenderness © CHRIS WIKOFF, 2015 over the lateral malleolar zone of the ankle and also tenderness on palpation 2. THE OTTAWA KNEE RULES9 over the posterior aspect of the lateral ankle, approximately 1 cm superior to In patients with acute knee injury, a knee x-ray is necessary if any of the the lateral malleolus. following criteria are met: Patella According to the Ottawa ankle rules, • Patient is aged 55 years or older this woman should have a radiograph • Isolated tenderness of the patella ­performed. The Ottawa rules have a very (Figure 2) high sensitivity but the specificity is • Tenderness at the head of the fibula fairly low at about 40%, meaning that (Figure 2) although the criteria for an x-ray may • Inability to flex the knee to 90° Head of fibula be met there is still a reasonable chance • Inability to bear weight both immediately a fracture may not be found. and in the emergency department The patient was informed that a radio­graph was indicated but she was Figure 2. Ottawa knee rules – regions of convinced it was just a severe sprain and bone tenderness. Adapted from Stiell et al., Ann Emerg Med 1995; 26: was eager to leave to pick her children 405-413.9 up from school. She reluctantly agreed © CHRIS WIKOFF, 2015

MedicineToday ❙ NOVEMBER 2015, VOLUME 16, NUMBER 11 49 Permission granted by Medicine Today for use on ResearchOnline@ND. © Medicine Today 2015 (www.medicinetoday.com.au) EMERGENCY MEDICINE continued

to the radiography. The x-ray showed an unstable Weber type B trimalleolar frac- Figures 3a and b. 14 Ankle fracture. ture of the fibula (Figure 3a; Table 1). a (far left). X-ray at The patient was admitted to hospital presentation. and her ankle was repaired surgically b (left). X-ray after with plates and screws (Figure 3b). surgical repair. ­Outpatient physio­therapy helped her recovery.

Case 2. A possible knee fracture A 22-year-old man, a semiprofessional soccer player, presented at the emergency department with right knee pain 24 hours after twisting his right knee while ‘turn- ing on the ball’. He reported pain and a ‘locking’ sensation in the right knee. On examination, the patient was able to bear weight on the affected leg and there was no deformity or obvious

TABLE 1. MANAGEMENT OF ANKLE FRACTURES14

Injury Description Management

Lateral malleolar fractures – Weber ankle fracture classification

Type A Fracture below the syndesmosis If stable fracture (undisplaced or minimally Avulsion fractures often associated with oblique or vertical displaced), nonoperative: medial malleolar fractures • walking cast ± crutches for 6 weeks • weight bear as tolerated in walking cast, cast can be taken off when not weightbearing • x-ray at 6 weeks – clinical union indicated by no pain at fracture site If unstable fracture, surgical repair (open reduction and internal fixation)

Type B Fracture begins at the joint level and extends proximally in an If stable fracture (undisplaced and mortice intact), oblique direction nonoperative: If accompanied by medial malleolus fracture or with deltoid • full below knee plaster with crutches ligament rupture, the ankle is considered unstable • repeat x-ray at 1 to 2 weeks • plaster for 6 weeks total • x-ray at 6 weeks out of plaster – clinical union indicated by no pain If unstable fracture, surgical repair (open reduction and internal fixation)

Type C Fractures above the joint line, usually with syndesmotic injury Surgical repair (open reduction and internal Can be associated with transverse avulsion medial malleolus fixation) fracture or deltoid ligament rupture

Other injury

Ligamentous Damage to any of the ligaments supporting the R – Rest injury ankle joint I – Ice C – Compression E – Elevation

50 MedicineToday ❙ NOVEMBER 2015, VOLUME 16, NUMBER 11 Permission granted by Medicine Today for use on ResearchOnline@ND. © Medicine Today 2015 (www.medicinetoday.com.au) effusion. Both lower limbs were warm TABLE 2. MANAGEMENT OF KNEE INJURIES15,16 and neurovascularly intact. He had a ­positive swipe test (a fluid wave bulge Injury Description Management just below the medial distal portion or patellar ­border on a particular pattern Extra-articular Supracondylar, in which the Undisplaced: groin to toe plaster fracture fracture does not extend to Displaced: surgically with of stroking the leg in the knee area) on the knee joint line intramedullary nails his right knee, consistent with a small effusion in the knee joint. There was joint Partial articular Partial articular or condylar, in Undisplaced: groin to toe plaster line tenderness on the medial aspect of fracture which the fracture extends to Displaced: surgically with the knee joint line but part of intramedullary nails the knee but no isolated patellar or fibular the condyles remain attached head tenderness. to the femur shaft The patient had a normal range of Complete Complete articular or Undisplaced: groin to toe plaster motion of both knees and the ligaments articular intercondylar, in which the Displaced: surgically with plate stabilising his knee joint (the anterior and fracture fracture extends to the knee and screws posterior cruciate ligaments and the joint line but the condyles are medial and lateral collateral ligaments) completely separated from the were intact. McMurray’s ligament test for femur shaft injury to the meniscus was positive Ligamentous Tear in the anterior cruciate, R – Rest (pain felt by the patient or a click felt injury posterior cruciate, medial I – Ice by patient or ­examiner on particular collateral or lateral collateral C – Compression ligament of the knee ­palpation of the knee). E – Elevation The combination of injury mechanism Surgical repair if major tear and clinical signs suggested medial present meniscus tear. The patient was informed Meniscal tear Tear in either the medial or R – Rest of this, and subsequently asked if he could lateral meniscus of the knee I – Ice have an x-ray to confirm the diagnosis. C – Compression It was explained to the patient that, E – Elevation based on the Ottawa knee rules, his chance NSAIDs of having a fracture in the knee was Physiotherapy extremely slim, with the rules having a Surgical repair if tear present in negative predictive value of 1. He agreed the vascularised outer third of the that radiography was unnecessary and was meniscus then discharged, within an hour of his presentation, with a referral for outpatient without exposing patients to x-rays. A injured joints. If applied correctly, they orthopaedic management. As an outpa- recent study in the USA has shown that, have the potential to reduce unnecessary tient he received advice to treat his knee with minimal training, orthopaedic x-ray exposure and cost in an acute set- with RICE (rest, ice, compression and registrars are able to use ultrasound ting, as well as avoiding significant incon- elevation) and use NSAIDs for pain relief imaging during the primary examina- venience to the patient. MT (Table 2).15,16 He subsequently received tion in the emergency department to physiotherapy for the injury. exclude significant ankle fractures.17 Acknowledgement In this situation, applying the Ottawa This could decrease the need for radio­ The author acknowledges with thanks the major knee rules allowed a much faster discharge graphic imaging, resulting in rapid contribution to this article made by Jennifer Preddy, of the patient from the emergency depart- diagnosis with no exposure to ionising a research student in the medical faculty of the University of New South Wales, Sydney. ment, without sacrificing patient care or radiation. outcome. This approach reduces unnec- References essary x-ray exposu­ re, which is particu- Conclusion A list of references is included in the website version larly important for a young person. The Ottawa ankle and knee rules have (www.medicinetoday.com.au) and the iPad app been proven to be highly sensitive version of this article. Possible new direction and specific for detecting fractures and New imaging techniques are being have been shown to significantly decrease developed to investigate acute injuries the need for radiographic imaging of COMPETING INTERESTS: None.

MedicineToday ❙ NOVEMBER 2015, VOLUME 16, NUMBER 11 51 Permission granted by Medicine Today for use on ResearchOnline@ND. © Medicine Today 2015 (www.medicinetoday.com.au) MedicineToday 2015; 16(11): 48-51 Acute ankle and knee injuries To x-ray or not?

GORDIAN FULDE MB BS, FRACS, FRCS(Ed), FRCS/FRCP(A&E)Ed, FACEM

References

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